The risk of human exposure to toxic dinoflagellate blooms during Chesapeake Bay fish kills was recently established by a medical team from the University of Maryland and John Hopkins University. The epidemiology greatly resembles that of previously described events associated with the toxic dinoflagellate, Pfiesteria piscicada. The life cycle of this organism is complex and characterized by multiphasic (greater than 24) life forms with both toxic and non-toxic stages. Appearance of the toxic stage in the environment is transient, and rapid cultivation is essential for isolation. Unfortunately, current identification requires in vitro propagation, morphological identification with light and scanning electron microscopy, and confirmation in a standard fish bioassay for toxicity. Preliminary data have indicated that Chesapeake Bay isolates may also include not only P. piscicida but also other related but distinct species. Multiple laboratory accidents have demonstrated the need for BLS3 level containment, and research has been hampered by lack of adequate facilities for the identification and culture of P. piscicida. Therefore, we are proposing the "Core Facility for the Culture of Toxic Dinoflagellates" in order to coordinate studies of harmful dinoflagellate blooms in the Chesapeake Bay. Specific aims of this facility will include: 1) Optimization of conditions for propagation and toxin production of monoclonal and, if possible, axenic cultures; 2) Development of detection methods for species-, toxin-, or stage-specific identification using molecular probes; Determination of more accurate, rapid, and sensitive bioassays for toxicity in order to investigate toxin induction and biosynthesis and its relationship to dinoflagellate life history. This facility will be centrally located in Baltimore, MD at the Center of Marine Biotechnology, a state of the art facility with two equipped BLS3 safety level containment laboratories. The Core Facility for the Culture of Toxic Dinoflagellates will provide cultures, methodology, and toxin samples for the coordinate and integrated efforts of researchers in environmental and genetic aspects as well as the medical community.